Iron Kissed - Patricia Briggs

When her former boss and mentor is arrested for murder, its up to shapeshifting car mechanic Mercy Thompson to clear his name, whether he wants her to or not. And she'll have to choose between the two werewolves in her life--whether she wants to or not. Original.
"Expect to be spellbound"* by Patricia Briggs's #1 New York Times bestselling series starring Mercy Thompson. Being a lowly "walker" in a world of vampires, werewolves, and fae once kept her safe. But Mercy's bark--and bite--are not so harmless any more...

Though Mercy can shift her shape into that of a coyote, her loyalty never wavers. So when her former boss and mentor, Zee, asks for her help, she's there for him. A series of murders has rocked a fae reservation, and Zee needs her unique gifts, namely her coyote sense of smell, to sniff out the killer.

But when Zee is accused of murdering the suspect Mercy outed, he's left to rot behind bars by his own kind. Now it's up to Mercy to clear his name, whether he wants her to or not.

Mercy's loyalty is under pressure from other directions, too. Werewolves are not known for their patience, and if Mercy can't decide between the two she cares for, Sam and Adam may make the choice for her...

*Lynn Viehl, New York Times bestselling author